Tuesday 12 December 2000
A new, low-cost, whole-body scanning technique which could revolutionise the detection and treatment of cancer and other diseases has been developed by researchers at The Institute of Cancer Research and The Royal Marsden Hospital.
The powerful new scanner - known as PETRRA - will allow doctors to detect the early onset of cancer and determine the rate of tumour growth. The scanner could be in hospitals within two years following the work of a consortium led by scientists from The Institute, in collaboration with the Rutherford Appleton Laboratories and the Royal Marsden.
Medical imaging forms a fundamental part of the diagnosis and treatment of diseases such as cancer. By providing a non-invasive method of detecting and monitoring changes in the body, imaging can be used to tailor treatment for patients and to investigate residual or recurring disease after therapy.
Bob Ott, Professor of Radiation Physics at The Institute of Cancer Research, and leader of the project, commented: "This is a significant breakthrough which could have major implications for the way in which the medical profession is able to detect and treat cancer and other diseases.
The new scanner performs Positron Emission Tomography which is a more sensitive detector of many cancers than conventional methods - for example x-rays - and can be far more specific about the malignancy of a tumour."
Traditional x-ray tomography (CT) and MRI (magnetic resonance imaging) scanners produce images of the anatomy. Instead, PETRRA monitors tissue function and 'converts' the findings into an image. Since there are often significant changes to tissue function before anatomy is altered, the new scanner can detect changes which anatomical scanners are unable to pick up.
To devise the new technique, Professor Ott's team at The Institute and Royal Marsden has drawn on particle and space physics technologies, to overcome the size and cost limitations of traditional Positron Emission Technology (PET) to develop an innovative, low-cost camera design.
The new technique has a number of advantages over traditional functional imaging methods. At nearly three times the size of a conventional PET camera, the new equipment is able to scan half the patient's body at once - as compared with a 16cm length of body scanned by conventional methods. This makes the new technique ideal for both detecting and monitoring the progress of treatment for widespread disease in cancer patients.
Additionally, the new scanner has been developed to be affordable to NHS hospitals - each machine should cost no more to purchase than a standard x-ray CT scanner.
Previous versions of the PET imaging camera were designed around an expensive system of multiple detectors and amplifiers which converted gamma rays into an electronic signal. The new system is made up of crystals mounted in a vacuum chamber, containing wire grids and a light-sensitive gas.
It works by detecting the gamma-rays emitted by minute quantities of radioactive tracers, known as radio-pharmaceuticals, which are administered to patients. The distribution of the tracers within the body is mapped by the scanner, allowing the clinician to monitor tissue function.
The process helps doctors to determine which tumours are benign or slow growing and which are malignant and developing quickly. For example, rapidly growing cancers use glucose for energy far more avidly than healthy tissues. By administering a tracer which mimics glucose, doctors can measure the rate of growth of the tumour according to the rate at which the substance is metabolised by the cancer.
Additionally, the new scanner has been designed to minimise discomfort for patients. Ample space inside the machine means it should prove less intimidating for those who experience anxiety when undergoing traditional scans.
Dr Peter Rigby, Chief Executive of The Institute of Cancer Research, said:
"This new technology will allow clinicians to detect and monitor cancer far more accurately than before. Importantly, it is also affordable to the NHS and we hope that PET will be making an impact on the treatment and detection of cancer in the NHS within the next 2-3 years."
Cally Palmer, Chief Executive of The Royal Marsden NHS Trust, said:
"Tests on the new scanner have shown it to be more successful in detecting the development of some cancers at an earlier stage than other technology available to us.
"This new technology will bring the benefits of PET scanning within the reach of hospitals around Britain and beyond. We are delighted to be involved at the forefront of this advance in healthcare."
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For more information, please contact the Institute of Cancer Research press office on:-
Tel: 0207 970 6030
email: [email protected]
Notes to Editors
- A version of the PET scanner has been available for 30 years - but these conventional PET cameras are prohibitive in cost to the NHS.
- The Institute of Cancer Research and The Royal Marsden NHS Trust together form the largest comprehensive cancer centre in Europe. By working in close partnership, research findings at The Institute are translated quickly into clinical care at The Marsden.
Technical Note:
- The distribution of the radio-pharmaceutical through the body is measured by monitoring tiny particles, or positrons, emitted from the tracer as a result of radioactive decay.
- The positron itself cannot be detected outside the body but, once emitted, it collides with an electron in nearby body tissue, causing the release of a short burst of energy in the form of two gamma rays.
- The gamma rays strike the crystal in the detector and create a burst of ultraviolet light. This stimulates the gas to release an electron which, in turn, is detected by the wires to create an 'image' of tissue function.
Please note:
Unfortunately the press office are unable to answer queries from the general public. For general cancer information please refer to The Institute's cancer information page.